THE HEXAGONAL PRINCIPLE . 
363 
that the cell is made hexagonal by the cutting away of mate- 
rial from six surrounding cells— they both agree in one point, 
namely, that the normal shape of the cell is cylindrical, and 
that it only assumes the hexagonal form by mechanical means. 
MISCHOCYTTARUS. 
I C ARIA. 
RAPHIGASTER. 
These questions were briefly mentioned, because an entire 
omission of them would appear negligent, but they were not 
followed up because the nests that would set them at rest be- 
longed to another group. We will first take the central nest. 
